The effect of surface roughness on rotor-stator cavity flows

Fernando, D.; Gao, Shian; Garrett, S. D.

doi:10.1063/1.5028209

Cited by 9 publications

(2 citation statements)

References 47 publications

(68 reference statements)

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“…Fernando et al used the general-purpose second-order finite volume method (FVM) solver and LES to conduct simulations of cavities with smooth surfaces at various Reynolds numbers. Then the properties of the mean turbulent flows are validated against experimental and numerical data available in the literature (Fernando et al, 2018). Bu et al (2017) provided a detailed explanation of flow transport between rotor and stator, which was not reported before.…”

Section: Analysis Of Thermal Flow Fieldmentioning

confidence: 99%

Calculation and analysis of thermal flow field in hydrodynamic torque converter with a new developed stress-blended eddy simulation

Yang

Liu

et al. 2021

HFF

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Purpose The flow phenomenon of particle image velocimetry has revealed the transition process of the complex multi-scale vortex between the boundary layer and mainstream region. Nonetheless, present computational fluid dynamics methods inadequately distinguish the discernable flows in detail. A multi-physical field coupling model, which was applied in rotor-stator fluid machinery (Umavathi, 2015; Syawitri et al., 2020), was put forward to ensure the identification of multi-scale vortexes and the improvement of performance prediction in torque converter. Design/methodology/approach A newly-developed multi-physical field simulation framework that coupled the scale-resolving simulation method with a dynamic modified viscosity coefficient was proposed to comparatively investigate the influence of energy exchange on thermal and flow characteristics and the description of the flow field in detail. Findings Regardless of whether quantitative or qualitative, its description ability on turbulence statistics, pressure-streamline, vortex structure and eddy viscosity ratio were visually experimentally and numerically analyzed. The results revealed that the modification of transmission medium viscous can identify flows more exactly between the viscous sublayer and outer boundary layer. Compared with RANS and large eddy simulation, a stress-blended eddy simulation model with a dynamic modified viscosity coefficient, which was further used to achieve blending on the stress level, can effectively solve the calculating problem of the transition region between the near-wall boundary layer and mainstream region. Research limitations/implications This indeed provides an excellent description of the transient flow field and vortex structure in different physical flow states. Furthermore, the experimental data has proven that the maximum error of the external performance prediction was less than 4%. Originality/value An improved model was applied to simulate and analyze the flow mechanism through the evolution of vortex structures in a working chamber, to deepen the designer with a fundamental understanding on how to reduce flow losses and flow non-uniformity in manufacturing.

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Section: Analysis Of Thermal Flow Fieldmentioning

confidence: 99%

Calculation and analysis of thermal flow field in hydrodynamic torque converter with a new developed stress-blended eddy simulation

Yang

Liu

et al. 2021

HFF

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“…Bridel-Bertomeu 62 components. Moreover, our recent publication 63 visualised the development of instability patterns on the rotor boundary layer of an identical rotor-stator cavity using a vortex identification method, 64 and the outcomes at Re ω = 1 × 10 5 have been compared with a higher Reynolds number case of Re ω = 4 × 10 5 . Figure 9 shows radial and tangential turbulence intensity profiles at r * = 0.50 for different volume fractions.…”

Section: B Single-phase Simulations Of Rotor-stator Nanofluidsmentioning

confidence: 99%

On the heat transfer effects of nanofluids within rotor-stator cavities

2018

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Owing to the rapid development of a number of technological and industrial sectors, high-performance electronic devices are now ubiquitous in modern engineering and industrial applications. Effective heat management is crucial to the smooth operation of such devices, and sometimes conventional methods of heat transfer fail to deliver the required performance. Recent advances in the field of nanofluids are a promising route to improve heat-transfer performance, and this is our motivation. We propose two computational fluid dynamics models for a rotor-stator cavity operating at Re ω = 1.0 × 10 5 and filled with a fluid that consists of different volume fractions of Al 2 O 3 nanoparticles. The first model simulates the nanofluid mixture using a single-phase transport model, and the second approach uses a two-phase transport model that allows for the relative velocity between the particle and fluid phases. All simulations are conducted using the second-order accurate solver, Open-FOAM®, that is based on the finite volume method and using Large eddy simulation methods. Our results show that the higher volume fractions of Al 2 O 3 nanoparticles can achieve higher heat transfer rates, and at the same time, dilute nanoparticle concentrations have subtle effects on the momentum transport of the system. This is an advantage over micro-particle dispersion. Furthermore, we consider the effects of particle forces in the two-phase model, such as Brownian and thermophoresis forces, and suggest that the thermophoresis forces are the dominant effect within the cavity geometry.

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